Keep holding note, intermittently acerbic, for old newsreader (4,5)
I believe the answer is:
town crier
'for old newsreader' is the definition.
(someone who delivered news in the past)
'keep holding note intermittently' is the wordplay.
'keep' becomes 'tower' (keep can mean a fortified structure).
'holding' indicates putting letters inside.
'note' becomes 'n' (abbreviation).
'intermittently' becomes 'cri' (I am not sure about this - if you are sure you should believe this answer much more).
'n'+'cri'='ncri'
'tower' enclosing 'ncri' is 'TOWN-CRIER'.
'acerbic' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for town crier that I've seen before include "He would have publicised" , "Formerly, an official who made public announcements" , "'The person who used to make public announcements in the streets (4,5)'" , "Bellman" , "old teller" .)